JP2009122674A - Developing agent and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing agent capable of making image quality high and performing melt adhesion at a relatively low temperature since it has satisfactory particle size distribution. <P>SOLUTION: The manufacturing method of developing agent includes forming a toner particle by adding an aggregating agent to a dispersion containing fine particles containing a binder resin and a colorant to make aggregation and melt fusion occur, wherein the pH of the dispersion satisfies formula (1): 0.90≥pH(C)/pH(A)≥0.25 and 1.00≥pH(C)/pH(B)≥0.30, when denoting pH before the addition of the aggregating agent by pH(A), the pH of the dispersion after the addition of the aggregating agent by pH(B), and the pH of the dispersion after the melt-adhesion by pH(C). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developer used in electrophotographic technology and the like and a method for producing the same.

  Conventionally, as a method for producing a toner in which the shape and surface composition of toner particles are intentionally controlled, aggregation and fusion are performed by using a metal salt or a polymer flocculant as a flocculant in a fine particle dispersion containing at least a resin and a colorant. An agglomeration method is proposed.

In this aggregation method, in order to accelerate the aggregation of the fine particles in the dispersion liquid in the aggregation process, the pH of the dispersion liquid is set lower than that before the aggregation, that is, the acid side is aggregated (for example, Patent Document 1, And Patent Document 2). Next, in order to stop aggregation and prevent coalescence, the pH was set higher than that at the time of aggregation, that is, on the basic side. Thereafter, the fusion process was performed at a high temperature. However, in this agglomeration method, since the glass transition temperature Tg is set higher than the glass transition temperature Tg in the fusing step and the coagulation fusing simultaneous step, there is a problem that the particle size distribution is shifted due to coalescence of the fusing particles and coarse particles are easily formed. there were. On the other hand, in order to prevent coalescence, there is a problem that fine powder is generated when the pH of the dispersion is made basic or redispersed by adding a surfactant. Due to such a problem, the image quality has deteriorated.
JP 2001-134017 A JP 2003-167380 A

  An object of the present invention is to provide a developer that can be fused at a relatively low temperature because of high image quality and good particle size distribution, and a method for producing the same.

In the method for producing a developer of the present invention, a coagulant is added to a dispersion containing fine particles containing a binder resin and a colorant to form aggregated particles, and the aggregated particles are fused to form toner particles. A method for producing a developer comprising:
The pH of the dispersion is pH (A) before adding the flocculant, pH (B) of the dispersion after adding the flocculant, and pH (C) of the dispersion after fusing. The following formula (1) is satisfied.

0.90 ≧ pH (C) / pH (A) ≧ 0.25 and 1.00 ≧ pH (C) / pH (B) ≧ 0.30 (1)
Further, the developer of the present invention includes toner particles obtained by adding an aggregating agent to a dispersion containing fine particles containing a binder resin and a colorant, and aggregating and fusing the particles.
The pH of the dispersion is pH (A) before adding the flocculant, pH (B) of the dispersion after adding the flocculant, and pH (C) of the dispersion after fusing. The following formula (1) is satisfied.

  0.90 ≧ pH (C) / pH (A) ≧ 0.25 and 1.00 ≧ pH (C) / pH (B) ≧ 0.30 (1)

  According to the present invention, it is possible to provide a developer capable of fusing at a relatively low temperature and a method for producing the same because of high image quality and good particle size distribution.

  The present invention relates to a method for producing a developer by an agglomeration method including a step of adding an aggregating agent to a dispersion containing fine particles containing at least a binder resin and a colorant, and aggregating and fusing. When the pH of the fine particle dispersion is pH (A), the pH of the dispersion after addition of the flocculant is pH (B), and the pH of the dispersion after fusion is pH (C), the following formula (1) By satisfying the expressed relationship, the process has a step of fusing at a predetermined temperature sufficient for fusing.

0.90 ≧ pH (C) / pH (A) ≧ 0.25 and 1.00 ≧ pH (C) / pH (B) ≧ 0.30 (1)
According to the present invention, after agglomeration, fusion can be performed by further adding an acid or a strong acid-weak base salt to lower the pH.

  According to the present invention, the glass transition temperature can be obtained with good particle size distribution by adding an acid or a strong acid-weak base salt after aggregation, before fusion, or when aggregation and fusion are performed in parallel. Fusion can be performed at a relatively low temperature of Tg + 35 ° C. or less.

  When pH (C) / pH (A)> 0.90, coalescence of aggregated particles does not occur, but the fusion temperature cannot be Tg + 35 ° C. or lower.

  In the case of 0.25> pH (C) / pH (A), the fusion temperature can be set to a predetermined temperature, for example, Tg + 35 ° C. or less, but the coalescence of aggregated particles cannot be prevented.

  When pH (C) / pH (B)> 1.00, coalescence of aggregated particles does not occur, but the fusion temperature cannot be set to a predetermined temperature, for example, Tg + 35 ° C. or less.

  In the case of 0.30> pH (C) / pH (B), the fusion temperature can be set to a predetermined temperature, for example, Tg + 35 ° C. or less, but aggregation of aggregated particles cannot be prevented.

  Further, when either pH (C) / pH (A) or pH (C) / pH (B) does not satisfy the formula (1), coalescence of aggregated particles occurs or a predetermined temperature, for example, Tg + 35 Cannot be fused below ℃.

  Even if the aggregation process and the fusion process are separate, the aggregation and the fusion process may be performed in parallel. When the aggregating step and the fusing step are different, the aggregating step can be terminated when the agglomerated particles become sufficiently large, and the process can proceed to the fusing step. In the case where the aggregation and the fusion are performed in parallel, the aggregation and the fusion can be repeated, and the fusion can be terminated when the aggregated particles reach a desired size.

  The fusing process is performed at a predetermined temperature, for example, a temperature not higher than 35 ° C. higher than the glass transition temperature of the binder resin.

  When the aggregation step and the fusion step are different, the pH adjustment can be performed once or more before, during, after, or during the fusion.

  In the case where the coagulation step and the fusion step are performed simultaneously, the pH adjustment can be performed at least once before or during the cohesion fusion.

  FIG. 1 shows a flow representing one embodiment of the developer production method of the present invention.

  As shown in the drawing, in the present invention, first, a dispersion of fine particles of toner material is prepared (Act 1).

  The fine particles of the toner material contain a colorant and a binder resin.

  The fine particles of the toner material also optionally contain a release agent and a charge control agent.

  The fine particles of the toner material can be formed by, for example, forming coarse particles in advance and then subjecting the obtained coarse particles to mechanical shearing in an aqueous medium. Coarse particles can be formed by, for example, melting and kneading a mixture containing a binder resin and a colorant and coarsely pulverizing the mixture.

  Optionally, at least one of a surfactant and a pH adjuster can be added to the aqueous medium.

  By adding the surfactant, the surfactant adsorbed on the surface of the mixture can be dispersed in the aqueous medium.

  Further, by adding a neutralizing agent, it is possible to improve the self-dispersibility by increasing the degree of dissociation of the dissociable functional group on the surface of the mixture or increasing the polarity.

  Subsequently, the obtained mixed liquid is subjected to mechanical shearing, and the coarse particles can be further finely granulated to form fine particles.

  Mechanical shearing can be performed by heating to a temperature equal to or higher than the glass transition temperature of the binder resin.

  According to the present invention, coarse particles can be finely divided and granulated by applying a mechanical shear force at a temperature equal to or higher than the glass transition temperature in an aqueous medium.

  By adjusting the processing temperature at the time of mechanical shearing, the processing time, the number of rotations of the apparatus for applying mechanical shearing, the pressure, and the like, the size of the obtained fine particles can be controlled.

  After mechanical shearing, the preferred size of the dispersion for forming the developer is preferably a volume average particle size of 0.01 to 1.5 μm. If it is smaller than 0.01 μm, it is difficult to produce particles, and if it is 1.5 μm or more, it tends to be difficult to produce particles of 3-10 μm. (Act 1).

  An example of the aggregation and fusion operation (Act 2) in the present invention will be described in more detail with reference to FIGS.

  FIG. 2 is a model diagram showing the state of particles in the aggregation and fusion operation when aggregation and fusion are different.

  As shown in the figure, the pH of dispersion A-1 containing fine particles before adding the flocculant is pH (A).

  It is also possible to add the pH adjusting agent (I) to the dispersion A-1 before adding the flocculant. By this pH adjustment, the promotion of aggregation and the fusing temperature can be reduced to Tg + 35 degrees or less.

Aggregation step When an aggregating agent is added to dispersion A-1, dispersion B-1 having a pH (B) is obtained. In this dispersion B-1, the fine particles 11 aggregate to form aggregated particles 12. It is also possible to add pH adjuster (II) to dispersion B-1. By this pH adjustment, the promotion of aggregation and the fusing temperature can be reduced to Tg + 35 degrees or less.

  When particles 13 having a desired size, for example, a volume average particle size of 3 to 10 μm are obtained, it is also possible to add a pH adjusting agent (III). By adjusting the pH, the fusing temperature can be reduced to Tg + 35 degrees or less.

Next, the dispersion obtained in the agglomeration step is heated to a temperature not higher than 35 ° C. higher than the glass transition temperature of the binder resin and allowed to stand, for example, for 0.5 to 3 hours for fusing. A dispersion C-1 having a pH (C) containing the fused particles 14 is obtained.

What is necessary is just to add at least 1 sort (s) among pH adjusters I, II, and III. The pH adjusting agent may be the same or different.

  FIG. 3 is a model diagram showing the state of particles in the aggregation and fusion operations when the aggregation and fusion proceed simultaneously.

  As shown in the figure, before adding the flocculant, the pH of dispersion A-2 containing fine particles is pH (A).

  When a flocculant is added to the dispersion A-2, a dispersion B-2 having a pH (B) is obtained. In this dispersion B-2, the fine particles 11 aggregate and fuse together to form aggregated fused particles 12 '. It is also possible to add a pH adjuster (IV) to the dispersion B-2. By this pH adjustment, the promotion of aggregation and the fusing temperature can be reduced to Tg + 35 degrees or less.

  When the desired size, for example, the volume average particle size becomes 3 to 10 μm, the cohesive fusion is terminated, and a dispersion C-2 having a pH (C) containing the fused particles 14 ′ is obtained.

What is necessary is just to add at least 1 sort (s) among pH adjusters I and IV. The pH adjusting agent may be the same or different.

  By cooling the dispersion liquid containing such fused particles 14 and 14 ′ to, for example, a glass transition temperature or lower (Act 3), and then washing (Act 4) using, for example, a filter press, and drying (Act 5), Toner particles are obtained.

  As a resin, a colorant, a release agent, a surfactant, a metal salt, a polymer flocculant, an acid, a neutralizer, a pH adjuster, and a mechanical shearing device used in the present invention, known materials and production All equipment can be used.

Resin material Examples of the binder resin used in the present invention include styrene resins such as polystyrene, styrene / butadiene copolymer, styrene / acrylic copolymer, polyethylene, polyethylene / vinyl acetate copolymer, polyethylene / norbornene copolymer. Examples thereof include ethylene resins such as coalescence, polyethylene / vinyl alcohol copolymer, polyester resins, acrylic resins, phenol resins, epoxy resins, allyl phthalate resins, polyamide resins, and maleic resins. These resins may be used alone or in combination of two or more.

  The binder resin preferably has an acid value of 1 or more.

Colorant Examples of the colorant used in the present invention include carbon black, organic or inorganic pigments and dyes. For example, carbon black includes acetylene black, furnace black, thermal black, channel black, ketjen black, and the like. Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 74, 81, 83, 93, 95, 97, 98, 109, 117, 120, 137, 138, 139, 147, 151, 154, 167, 173, 180, 181, 183, 185, C.I. I. Bat yellow 1, 3, 20, etc. are mentioned. These may be used alone or in combination. Examples of magenta pigments include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 150, 163, 184, 185, 202, 206, 207, 209, 238, C.I. I. Pigment violet 19, C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35, etc. are mentioned. These may be used alone or in combination. Examples of cyan pigments include C.I. I. Pigment blue 2, 3, 15, 16, 17, C.I. I. Bat Blue 6, C.I. I. Acid Blue 45 and the like. These may be used alone or in combination.

Release Agent Examples of the release agent used in the present invention include, for example, low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, aliphatic hydrocarbon wax such as Fischer-Tropsch wax, oxidation Oxides of aliphatic hydrocarbon waxes such as polyethylene wax, or block copolymers thereof, plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax, rice wax, beeswax, lanolin, whale wax Animal waxes such as ozokerite, ceresin, mineral waxes such as petrolactam, waxes based on fatty acid esters such as montanic acid ester wax and castor wax, deoxidized carnauba wax, etc. Examples include those obtained by partially or fully deoxidizing fatty acid esters. Further, saturated linear fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a long-chain alkyl group, unsaturated fatty acids such as brassic acid, eleostearic acid, valinalic acid, stearyl alcohol , Saturated alcohols such as eicosyl alcohol, behenyl alcohol, carnauvir alcohol, seryl alcohol, melyl alcohol, or long chain alkyl alcohols having a long chain alkyl group, polyhydric alcohols such as sorbitol, linoleic acid amide, oleic acid Amide, fatty acid amide such as lauric acid amide, methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, saturated fatty acid bisamide such as hexamethylene bisstearic acid amide, Unsaturated fatty acid amides such as lenbis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide, m-xylene bis stearic acid amide, Aromatic bisamides such as N, N'-distearylisophthalic amide, fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (generally referred to as metal soap), aliphatic Hydroxyl obtained by hydrogenating waxes grafted to hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid, partially esterified products of fatty acids and polyhydric alcohols such as behenic acid monoglycerides, and vegetable oils and fats. Methyl Este Having a Group Compounds.

Surfactant Examples of the surfactant that can be used in the present invention include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap, amine salt type, quaternary ammonium salt, and the like. Nonionic surfactants such as cationic surfactants such as molds, polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols.

Metal salts Examples of metal salts that can be used in the aggregation step of the present invention include sodium chloride, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, magnesium sulfate, aluminum chloride, aluminum sulfate, and potassium aluminum sulfate. Examples thereof include salts, and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide.

Polymer flocculants The polymer flocculants that can be used in the flocculation process of the present invention include polymethacrylate, polyacrylate, polyacrylamide, sodium acrylamide acrylate copolymer, polyamine, polydiallylammonium halide, poly Examples thereof include polymer flocculants such as dimethyl diallyl ammonium halide, melanin formaldehyde condensate, and dicyandiamide.

Acid Acids that can be used in the aggregation step of the present invention include hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, acetic acid, citric acid, and the like.

Neutralizing agent As the neutralizing agent usable in the present invention, inorganic bases and amine compounds can be used. Examples of inorganic bases include sodium hydroxide and potassium hydroxide. Examples of amine compounds include dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, sec-butylamine, monoethanolamine, diethanolamine, triethanolamine, triisopropanolamine. , Isopropanolamine, dimethylethanolamine, diethylethanolamine, N-butyldiethanolamine, N, N-dimethyl-1,3-diaminopropane, N, N-diethyl-1,3-diaminopropane and the like.

Mechanical shearing device Examples of the mechanical shearing device used in the present invention include Ultra Tarrax (manufactured by IKA Japan), TK auto homomixer (manufactured by Primix), and TK pipeline homomixer (manufactured by Primix). , TK Philmix (manufactured by Primix), Claremix (manufactured by M Technique), Claire SS5 (manufactured by M Technique), Cavitron (manufactured by Eurotech), fine flow mill (manufactured by Taiheiyo Kiko) Medialess stirrer, Viscomill (manufactured by Imex), Apex mill (manufactured by Kotobuki Kogyo Co., Ltd.), Starmill (manufactured by Ashizawa, Finetech), DCP Super Flow (manufactured by Japan Eirich), MP Mill (manufactured by Inoue Seisakusho), spike Mill (manufactured by Inoue Seisakusho), Mighty mill (Inoue Seisakusho Co., Ltd.) ), SC mill (Mitsui Mining Co., Ltd.) and other media stirrers, etc., and high-pressure impact dispersion devices such as an optimizer (Sugino Machine Co., Ltd.), Nanomizer (Yoshida Kikai Co., Ltd.), and NANO 3000 (Migrain Co., Ltd.). It is done.

pH adjuster As the pH adjuster used in the present invention, in order to lower the pH, for example, hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, acetic acid, citric acid and the like, and aluminum sulfate, aluminum chloride, ammonium sulfate, Examples include strong acid-weak base salts such as ammonium chloride. Moreover, in order to raise pH, bases, such as sodium hydroxide, potassium hydroxide, ammonia, a triethylamine, are mentioned, for example.

Examples Hereinafter, the present invention will be described more specifically with reference to examples.

The characteristics and particle size of the resin were determined by the following method.

Glass Transition Temperature (Tg) Measurement The glass transition temperature used in the present invention was measured at a rate of 10 ° C./min using a DSC8230 manufactured by Rigaku Corporation, and the range of 40 to 200 ° C. was measured. The shoulder value obtained by the tangent method from the DSC curve obtained under these measurement conditions is defined as the glass transition temperature.

Measurement of softening point (Tm) The softening point used in the present invention is determined by a flow tester method using CFT-500D manufactured by Shimadzu Corporation. The measurement conditions are: die: 1.0 × 1.0 mm, heating rate: 2.5 ° C./min, load: 10 kg, temperature range: 40-200 ° C., preheating time: 300 s, and the outflow start temperature is the softening point. .

Particle size distribution measurement In the present invention, the particle size distribution of the resin, pigment, and release agent mixed dispersion is measured using SLAD-7000 manufactured by Shimadzu Corporation.

  The average particle size before pH adjustment can be measured using an aperture (diameter 20 μm) of Multisizer 3 manufactured by Beckman Coulter. The average particle diameter of the toner is measured using an aperture (diameter: 100 μm) of Multisizer 3 manufactured by Beckman Coulter.

Preparation of resin / pigment / release agent mixed dispersion 1 90 parts by weight of polyester resin (Tg: 62 ° C., Tm: 115 ° C.) as binder resin, 5 parts by weight of copper phthalocyanine pigment as colorant, and ester wax 5 as release agent After mixing the parts by weight, the mixture was melt kneaded in a biaxial kneader set at a temperature of 120 degrees to obtain a kneaded product.

  The obtained kneaded product was coarsely pulverized to a volume average particle size of 1.2 mm using a hammer mill manufactured by Nara Machinery Co., Ltd. to obtain coarse particles.

  40 parts by weight of coarse particles, 1 part by weight of sodium dodecylbenzenesulfonate as an anionic surfactant, 1 part by weight of triethylamine as an amine compound, and 59 parts by weight of ion-exchanged water are added to CLEARMIX, and the dispersion is heated to 120 degrees. After that, the number of revolutions of CLEARMIX was set to 6500 rpm, and after mechanical stirring for 30 minutes, the mixture was cooled to room temperature to prepare a dispersion having a volume average particle size of 480 nm. The pH of the obtained dispersion was 8.6.

Preparation of resin / pigment / release agent mixed dispersion 2 90 parts by weight of polyester resin (Tg: 62 ° C., Tm: 115 ° C.) as binder resin, 5 parts by weight of copper phthalocyanine pigment as colorant, and ester wax 5 as release agent After mixing the parts by weight, the mixture was melt kneaded in a biaxial kneader set at a temperature of 120 degrees to obtain a kneaded product.

  The obtained kneaded product was coarsely pulverized to a volume average particle size of 1.2 mm using a hammer mill manufactured by Nara Machinery Co., Ltd. to obtain coarse particles.

  The coarse particles were medium pulverized to a volume average particle size of 0.05 mm using a bantam mill manufactured by Hosokawa Micron Corporation to obtain intermediate crushed particles.

  40 parts by weight of crushed particles, 1 part by weight of sodium dodecylbenzenesulfonate as an anionic surfactant, 1 part by weight of triethylamine as an amine compound, and 59 parts by weight of ion-exchanged water were treated with NANO3000 at 150 MPa and 180 ° C., volume A dispersion having an average particle size of 350 nm was prepared. The pH of the obtained dispersion was 8.5.

Example 1
Aggregation / fusion process 50 parts by weight of the dispersion 1 and 30 parts by weight of ion-exchanged water were added and mixed. The pH (A) of the dispersion at this time was 8.5. When 20 parts by weight of a 10% by weight aqueous sodium chloride solution was added as a metal salt at room temperature, the pH (B) was 8.3. Subsequently, the temperature of the dispersion was raised to 75 ° C., and when the volume average particle size reached 2.4 μm, hydrochloric acid was added to adjust the pH to 3.0, and then 2 hours at 75 ° C. to control the particle size and shape. I left it alone. The resulting dispersion after fusion pH (C) was 3.0.

Washing and drying step After cooling, the solid content of the obtained dispersion is repeatedly centrifuged with a centrifuge, the supernatant liquid removed, and washed with ion-exchanged water, and the conductivity of the supernatant becomes 50 μS / cm. Until washed. Then, it was dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles.

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the toner particle surface to obtain a toner.

  The obtained toner had a volume average particle size of 5.32 μm.

  The results are shown in Table 1-1 and Table 1-2 below.

  When the toner particle size distribution was measured using a Multisizer 3 aperture (diameter 20 μm) manufactured by Beckman Coulter, the number of particles having a number particle diameter of 2 microns or less was a favorable result of 4.5%.

  Further, the obtained toner was put into a copying machine e-STUDIO 281c manufactured by TOSHIBA TEC which was modified for evaluation, and as a result of evaluating the image quality, a good image quality was obtained.

Example 2
Aggregation step 50 parts by weight of the dispersion 2 and 30 parts by weight of ion-exchanged water were added and mixed. The pH (A) was 8.4. When 20 parts by weight of a 20% by weight aqueous sodium chloride solution was added as a metal salt at room temperature, the pH (B) was 8.3. Subsequently, the dispersion was heated to 60 ° C., and sulfuric acid was added when the volume average particle diameter reached 1.9 μm. After adjusting the pH to 4.0, the temperature was raised to 65 ° C.

Fusing step 3 parts by weight of sodium dodecylbenzenesulfonate was added as a dispersant to maintain the volume average particle size of the aggregated particles, and the temperature was raised to 80 ° C. to control the shape, and left for 2 hours. The resulting dispersion after fusion pH (C) was 4.0.

Washing and drying step After cooling, the obtained dispersion was washed with a centrifuge in the same manner as in Example 1 and dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles. .

After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the toner particle surface to obtain a desired toner.

The obtained toner had a volume average particle diameter of 4.86 μm.

  The results are shown in Table 1-1 and Table 1-2 below.

When the toner particle size distribution was measured using a Multisizer 3 aperture (diameter: 20 μm) manufactured by Beckman Coulter, the number of particles having a particle diameter of 2 microns or less was found to be 6.1%.

  Further, the obtained toner was put into a copying machine e-STUDIO 281c manufactured by TOSHIBA TEC which was modified for evaluation, and as a result of evaluating the image quality, a good image quality was obtained.

Example 3
Aggregation step 50 parts by weight of the dispersion 1 and 30 parts by weight of ion-exchanged water were added and mixed. The pH (A) was 8.5. When 20 parts by weight of a 20% by weight sodium chloride aqueous solution was added as a metal salt at room temperature, the pH (B) was 8.2. Subsequently, the dispersion was heated to 65 degrees.

Fusion process 3 parts by weight of sodium dodecylbenzenesulfonate is added as a dispersant to maintain the volume average particle size of the aggregated particles, the temperature is raised to 85 ° C. to control the shape, and the pH is adjusted to 5.5 with hydrochloric acid. Adjust and let stand for 2 hours. The resulting dispersion after fusion pH (C) was 5.5.

Washing and drying step After cooling, the obtained dispersion was washed with a centrifuge in the same manner as in Example 1 and dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles. .

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the toner particle surface to obtain a desired toner.

  The obtained toner had a volume average particle size of 4.93 μm.

  The results are shown in Table 1-1 and Table 1-2 below.

When the toner particle size distribution was measured using a Multisizer 3 aperture (diameter 20 μm) manufactured by Beckman Coulter, the number of particles having a number particle diameter of 2 microns or less was a good result of 5.8%.

  Further, the obtained toner was put into a copying machine e-STUDIO 281c manufactured by TOSHIBA TEC which was modified for evaluation, and as a result of evaluating the image quality, a good image quality was obtained.

Example 4
Aggregation / fusion process 25 parts by weight of the dispersion 1 and 55 parts by weight of ion-exchanged water were added and mixed. The pH (A) was 8.4. When 10 parts by weight of a 10% by weight sodium chloride aqueous solution as a metal salt and 10 parts by weight of 5% by weight polydimethyldiallylammonium chloride as a polymer flocculant were added at room temperature, the pH (B) was 6.8. Subsequently, the temperature was raised to 90 ° C., hydrochloric acid was added to adjust to pH 6.0, and the mixture was allowed to stand for 2 hours in order to control the particle size and shape while agglomeration and fusion proceeded simultaneously. The resulting dispersion after fusion pH (C) was 6.0.

After cooling in the washing and drying step, the obtained dispersion was washed with a centrifuge in the same manner as in Example 1, and dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles. .

After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the toner particle surface to obtain a desired toner.

The obtained toner had a volume average particle size of 4.98 μm.

  The results are shown in Table 1-1 and Table 1-2 below.

When the toner particle size distribution was measured using a Multisizer 3 aperture (diameter: 20 μm) manufactured by Beckman Coulter, the number of particles having a particle diameter of 2 microns or less was 6.8%.

  Further, the obtained toner was put into a copying machine e-STUDIO 281c manufactured by TOSHIBA TEC which was modified for evaluation, and as a result of evaluating the image quality, a good image quality was obtained.

Example 5
Aggregation step 25 parts by weight of the dispersion 1 and 55 parts by weight of ion-exchanged water were added and mixed. The pH (A) was 8.4. After adjusting the pH to 7.5 by adding hydrochloric acid, 20 parts by weight of a 1% by weight aluminum sulfate aqueous solution was added as a metal salt at room temperature, resulting in a pH (B) of 6.5. Subsequently, the temperature was raised to 50 degrees.

Fusion process 5 parts by weight of sodium dodecylbenzenesulfonate was added as a dispersant in order to maintain the volume average particle size of the aggregated particles, and the temperature was raised to 90 degrees and left for 3 hours to control the shape. The resulting dispersion after fusion pH (C) was 6.5.

Washing and drying step After cooling, the obtained dispersion was washed with a centrifuge in the same manner as in Example 1 and dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles. .

After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the toner particle surface to obtain a desired toner.

  The obtained toner had a volume average particle diameter of 5.06 μm.

  The results are shown in Table 1-1 and Table 1-2 below.

When the toner particle size distribution was measured using a Multisizer 3 aperture (diameter: 20 μm) manufactured by Beckman Coulter, the number of particles having a number particle diameter of 2 microns or less was a good result of 8.7%.

  Further, the obtained toner was put into a copying machine e-STUDIO 281c manufactured by TOSHIBA TEC which was modified for evaluation, and as a result of evaluating the image quality, a good image quality was obtained.

Example 6
Aggregation step 25 parts by weight of the dispersion 1 and 55 parts by weight of ion-exchanged water were added and mixed. The pH (A) was 8.4. When 20 parts by weight of a 1% by weight aqueous aluminum sulfate solution was added as a metal salt at room temperature, pH (B) was 7.0. Subsequently, the dispersion was heated to 55 degrees.

Fusion process To maintain the volume average particle size of the aggregated particles, 5 parts by weight of sodium dodecylbenzenesulfonate is added as a dispersant, adjusted to pH 5.0 by adding hydrochloric acid, and then heated to 90 degrees to control the shape. And left for 2 hours. The resulting dispersion after fusion pH (C) was 5.0.

Washing and drying step After cooling, the obtained dispersion was washed with a centrifuge in the same manner as in Example 1 and dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles. .

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the toner particle surface to obtain a toner.

  The obtained toner had a volume average particle diameter of 5.26 μm.

  The results are shown in Table 1-1 and Table 1-2 below.

When the toner particle size distribution was measured using a Multisizer 3 aperture (diameter: 20 μm) manufactured by Beckman Coulter, the number of particles having a number particle diameter of 2 microns or less was a favorable result of 9.7%.

  Further, the obtained toner was put into a copying machine e-STUDIO 281c manufactured by TOSHIBA TEC which was modified for evaluation, and as a result of evaluating the image quality, a good image quality was obtained.

Comparative Example 1
Aggregation / fusion process 50 parts by weight of dispersion 1 and 30 parts by weight of ion-exchanged water were added and mixed. The pH (A) was 8.5. When 20 parts by weight of a 15% by weight sodium chloride aqueous solution was added as a metal salt at room temperature, the pH (B) was 8.2. Subsequently, the dispersion was heated to 100 ° C. and left for 3 hours in order to control the particle size and shape while agglomeration and fusion proceeded simultaneously. The pH (C) of the dispersion after completion of the fusion was 8.2.

Washing and drying step After cooling, the obtained dispersion was washed with a centrifuge in the same manner as in Example 1 and dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles. .

After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the toner particle surface to obtain a desired toner.

  The obtained toner had a volume average particle diameter of 4.83 μm.

  The results are shown in Table 1-1 and Table 1-2 below.

When the toner particle size distribution was measured using an aperture (diameter: 20 μm) of Multisizer 3 manufactured by Beckman Coulter, the result was 12.5% of particles having a number particle diameter of 2 microns or less.

  Further, the obtained toner was put into a copying machine e-STUDIO 281c manufactured by TOSHIBA TEC which was modified for evaluation, and the image quality was evaluated. As a result, the image quality deteriorated.

Comparative Example 2
Aggregation step 25 parts by weight of dispersion 1 and 55 parts by weight of ion-exchanged water were added and mixed. The pH (A) was 8.5. When 20 parts by weight of a 1% by weight aluminum sulfate aqueous solution was added as a metal salt at room temperature, the pH (B) was 7.1. Subsequently, the dispersion was heated to 55 ° C.

Fusing Step 5 parts by weight of sodium dodecylbenzenesulfonate was added as a dispersant to maintain the volume average particle size of the aggregated particles, and the temperature was raised to 98 ° C. and left for 3 hours to control the shape. The resulting dispersion after fusion pH (C) was 8.0.

Washing and drying step After cooling, the obtained dispersion was washed with a centrifuge in the same manner as in Example 1 and dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles. .

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the toner particle surface to obtain a desired toner.

  The obtained toner had a volume average particle size of 4.96 μm.

  The results are shown in Table 1-1 and Table 1-2 below.

  When the particle size distribution of the toner was measured using a Multisizer 3 aperture (diameter: 20 μm) manufactured by Beckman Coulter, the number of particles having a number particle diameter of 2 microns or less was 13.8%.

  Further, the obtained toner was put into a copying machine e-STUDIO 281c manufactured by TOSHIBA TEC which was modified for evaluation, and the image quality was evaluated. As a result, the image quality deteriorated.

Comparative Example 3
Aggregation / fusion process 25 parts by weight of the dispersion 1 and 55 parts by weight of ion-exchanged water were added and mixed. The pH (A) was 8.5. When 10 parts by weight of a 10% by weight sodium chloride aqueous solution as a metal salt and 10 parts by weight of 5% by weight polydimethyldiallylammonium chloride as a polymer flocculant were added at room temperature, the pH (B) was 6.8. Subsequently, the dispersion was heated to 100 ° C., and the dispersion was allowed to stand for 2 hours in order to control the particle size and shape while simultaneously proceeding aggregation and fusion. After completion of the fusion, the pH (C) of the dispersion was 7.0.

Washing and drying step After cooling, the obtained dispersion was washed with a centrifuge in the same manner as in Example 1 and dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles. .

After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the toner particle surface to obtain a desired toner.

  The obtained toner had a volume average particle diameter of 4.74 μm.

  The results are shown in Table 1-1 and Table 1-2 below.

  When the toner particle size distribution was measured using a Multisizer 3 aperture (diameter: 20 μm) manufactured by Beckman Coulter, the result was 11.7% of particles having a number particle diameter of 2 microns or less.

  Further, the obtained toner was put into a copying machine e-STUDIO 281c manufactured by TOSHIBA TEC which was modified for evaluation, and the image quality was evaluated. As a result, the image quality deteriorated.

Comparative Example 4
Aggregation step 50 parts by weight of the dispersion 1 and 30 parts by weight of ion-exchanged water were added and mixed. The pH (A) of the obtained dispersion was 8.5. When 20 parts by weight of a 20% by weight aqueous sodium chloride solution was added as a metal salt at room temperature, the pH (B) was 8.2. Subsequently, the dispersion was heated to 60 ° C., and when the volume average particle size became 2.3 μm, hydrochloric acid was added to adjust the pH to 2.0, and then the temperature was increased to 65 ° C.

Fusing Step 3 parts by weight of sodium dodecylbenzenesulfonate as a dispersant was added to the above aggregated particles, and the temperature was raised to 75 ° C. to control the shape and left for 1.5 hours. The pH (C) of the dispersion after completion of the fusion was 2.0.

Washing and drying step After cooling, the obtained dispersion was washed with a centrifuge in the same manner as in Example 1 and dried with a vacuum dryer until the water content became 0.3% by weight to obtain toner particles. .

  After drying, as additives, 2 parts by weight of hydrophobic silica and 0.5 parts by weight of titanium oxide were adhered to the toner particle surface to obtain a desired toner.

  The obtained toner had a volume average particle diameter of 13.8 μm.

  The results are shown in Table 1-1 and Table 1-2 below.

  The particle size could not be 3-10 μm.

  Further, the obtained toner was put into a copying machine e-STUDIO 281c manufactured by TOSHIBA TEC which was modified for evaluation, and the image quality was evaluated. As a result, the image quality deteriorated.

By taking such a structure, the fusion | melting temperature of binder resin can be lowered | hung below the temperature 35 degreeC higher than Tg.

FIG. 3 is a flowchart showing one embodiment of the developer manufacturing method of the present invention. Model diagram showing the state of particles in agglomeration and fusion operations when agglomeration and fusion are separate Model diagram showing the state of particles in agglomeration and fusion operations when agglomeration and fusion proceed simultaneously

Claims (12)

A method for producing a developer comprising forming a toner particle by adding a flocculant to a dispersion liquid containing fine particles containing a binder resin and a colorant, and aggregating and fusing the dispersion.
The pH of the dispersion is pH (A) before adding the flocculant, pH (B) of the dispersion after adding the flocculant, and pH (C) of the dispersion after fusing. A method for producing a developer satisfying the following formula (1).
0.90 ≧ pH (C) / pH (A) ≧ 0.25 and 1.00 ≧ pH (C) / pH (B) ≧ 0.30 (1)   The method for producing a developer according to claim 1, comprising adding a pH adjusting agent to the dispersion at least once.   The method according to claim 1, wherein the fine particles are aggregated and fused separately or in parallel.   The method according to claim 1, wherein the fusion of the fine particles is performed at a temperature not higher than 35 ° C. higher than the glass transition temperature of the binder resin.   The method according to claim 1, wherein the flocculant uses at least one of a metal salt, a polymer flocculant, and an acid. The method according to claim 1, wherein the glass transition temperature Tg of the binder resin, its softening point Tm, and the fusing temperature t of the developer satisfy the following formula (2).
Tg <t <Tm (2) A binder resin, and toner particles that are aggregated and fused by adding an aggregating agent to a dispersion containing fine particles containing a colorant;
The pH of the dispersion is pH (A) before adding the flocculant, pH (B) of the dispersion after adding the flocculant, and pH (C) of the dispersion after fusing. A developer satisfying the following formula (1).
0.90 ≧ pH (C) / pH (A) ≧ 0.25 and 1.00 ≧ pH (C) / pH (B) ≧ 0.30 (1)   The developer according to claim 7, comprising adding a pH adjusting agent to the dispersion at least once.   The developer according to claim 7, wherein the fine particles are aggregated and fused separately or in parallel.   The developer according to claim 7, wherein the fine particles are fused at a temperature not higher than 35 ° C. higher than the glass transition temperature of the binder resin.   The developer according to claim 7, wherein the flocculant uses at least one of a metal salt, a polymer flocculant, and an acid. The developer according to claim 7, wherein a glass transition temperature Tg of the binder resin, a softening point Tm thereof, and a fusing temperature t of the developer satisfy the following formula (2).
Tg <t <Tm (2)

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